In the Chittagong Hills of Bangladesh the rat population explodes, triggered by the mass flowering of bamboo plants that leads to a sudden increase in available food. Once the bamboo seeds are consumed the rats swarm into the rice fields and houses of farmers, eating everything they can find. The UN Development Programme commissioned Natural Resources Institute’s (NRI) expert in ecologically-based and sustainable rodent management strategies, Dr Steven Belmain, to research and find solutions for dealing with the problem.
Research on the ecology and biology of rodents in African and Asian agro-ecosystems has been carried out through a number of research projects, which have focussed on several multidisciplinary factors related to rodents and their sustainable control including: rodent population dynamics, systematics and taxonomy, habitat utilisation, rodent behaviour, outbreak ecology, social anthropology, economics, damage assessment methodologies, and the development of non-chemical rodent population control and impact mitigation strategies.
Global research on rodents as pests continues to be neglected by most developed economies. Although rodents are problematic in most urban and agricultural environments, their problems are much more severe in developing economies because people’s proximity to rodents is much higher in poor communities. In these situations, people live in buildings that are not rodent-proof, and often inadvertently encourage rodents into their houses by openly storing large quantities of food within. Poor sanitation and agriculture encourage rodent numbers, and their free movement between different habitats increases zoonosis transmission (the transmitting of infectious disease from animals to humans), food and water contamination, and pre and post-harvest crop losses.
The research of NRI has focussed on developing technologies and strategies that are relevant to the local agro-ecological and sociological contexts found within African and Asian societies. The result of these developments will be to reduce the multiple impacts of rodents on people’s livelihoods.
Dr Belmain, who is an ecologist from NRI’s Agriculture, Health and Environment Department, has led a number of research and development grants about rodent biology and management, investigating agricultural and human health problems caused by rodents, including work on the eco-epidemiology of bubonic plague, Lassa fever, toxoplasmosis, leptospirosis and cropping systems of rice production (lowland and highland), maize, millet, sorghum, vegetables and post-harvest food storage as well as rodents in non-agricultural ecologies such as bamboo forests.
The main findings of this research are that rodents and the damage they cause can be sustainably managed without the use of poisons. This can be done through strengthening communities to deal with shared problems, intensive trapping and trap barrier systems and environmental management that reduce the proximity of rodents to people. Case-control studies of Dr Belmain’s research have shown that rodent damage to crops can be reduced by greater than 75% in ways that are environmentally sustainable and cost-beneficial to subsistence farming communities in Africa and Asia.
In response to Dr Belmain’s research, governments in South Africa and Bangladesh have changed policies and practice with regards to rodent management. Moreover, the research outcomes have been incorporated into knowledge extension programmes operated by government and non-government organisations that target farmers.
Impact and benefits
Rodent outbreaks in the Chittagong Hill Tracts of Bangladesh are an unusual 50-year phenomenon driven by gregarious bamboo flowering. The bamboo seed-masting fuels exponential rodent breeding over many months which then lead to massive crop losses as rodents migrate out of forests. Because this happens rarely and in a specific region, awareness across all sectors of society in Bangladesh, from government to the public, was very low. This research was able to inform international relief efforts in the region carried out by UNDP, WFP, Save the Children, and many NGOs to understand the scale of the regional famine occurring.
In South Africa, research has had several impacts on national and regional policies. For example, through Dr Belmain’s activities, the National Pesticide Regulation Authority of the country has changed its regulations with respect to training requirements of pest control operators, to include a separate course on rodents which pest control operators must take if they wish to deal with rodent pest matters. Research undertaken in South Africa has led to the South African Department of Health establishing a plague surveillance expert panel and now routinely surveys “at risk” areas for plague outbreaks.
Elsewhere in Africa, particularly in Swaziland, Tanzania and Namibia, research within the ECORAT project has shown local authorities and rural agricultural communities how rodent pests can be sustainably controlled without the use of dangerous acute poisons. Local authorities in these countries are now advocating the use of intensive trapping and ecologically-based rodent management strategies for rodent control within their agricultural extension programmes.
Through projects like the above, NRI develops its research and consultancy expertise, delivering greater understanding and practical solutions to issues which quantify and mitigate major challenges such as climate change, globalisation, conflict, emergent diseases and major migratory pests which can all increase vulnerability and threaten the livelihood and health of the world’s poorest people.